vfio/pci: Clear MSI-X IRQ index always

When doing device assignment of a physical device, MSI-X can be
enabled with no vectors enabled and this sets the IRQ index to
VFIO_PCI_MSIX_IRQ_INDEX. However, when MSI-X is disabled, the IRQ
index is left untouched if no vectors are in use. Then, when INTx
is enabled, the IRQ index value is considered incompatible (set to
MSI-X) and VFIO_DEVICE_SET_IRQS fails. QEMU complains with :

qemu-system-x86_64: vfio 0000:08:00.0: Failed to set up TRIGGER eventfd signaling for interrupt INTX-0: VFIO_DEVICE_SET_IRQS failure: Invalid argument

To avoid that, unconditionaly clear the IRQ index when MSI-X is
disabled.

Buglink: https://issues.redhat.com/browse/RHEL-21293
Fixes: 5ebffa4e87 ("vfio/pci: use an invalid fd to enable MSI-X")
Cc: Jing Liu <jing2.liu@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Cédric Le Goater 2024-01-25 14:27:36 +01:00
parent 850051b94b
commit d2b668fca5

View File

@ -826,9 +826,11 @@ static void vfio_msix_disable(VFIOPCIDevice *vdev)
}
}
if (vdev->nr_vectors) {
vfio_disable_irqindex(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX);
}
/*
* Always clear MSI-X IRQ index. A PF device could have enabled
* MSI-X with no vectors. See vfio_msix_enable().
*/
vfio_disable_irqindex(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX);
vfio_msi_disable_common(vdev);
vfio_intx_enable(vdev, &err);